Near infrared (NIR) absorbing compounds have useful applications in digital imaging. These compounds absorb near infrared radiation but have minimal absorption in the visible spectrum, thus, they are virtually transparent to the naked eye. Near IR radiation is commonly defined as radiation with a wavelength between 700 nm and 1,400 nm. Known NIR absorbing compounds include carbon black, inorganic pigments, metals, organic dyes, and organic pigments. To be highly useful in many applications, NIR absorbing compounds must have certain properties in addition to absorption at the desired wavelength.
The present disclosure generally relates to a dispersion of near infrared (NIR) absorbing pigments that is useful as invisible tracers in ink and coating compositions, and a method of manufacturing such dispersion. The novel aspects and advantages of the present disclosure will become apparent from the following discussion.